package cn.rocky.prepare;

public class mergeTwoLists {


    public class ListNode {
        int val;
        ListNode next;

        ListNode() {
        }

        ListNode(int val) {
            this.val = val;
        }

        ListNode(int val, ListNode next) {
            this.val = val;
            this.next = next;
        }
    }

    /**
     * 有序的链表(递归,迭代)
     * @return
     */
    public ListNode mergeTwoLists(ListNode list1, ListNode list2) {
        if (list1 == null) {return list2;}
        else if (list2 == null) {return list1;}
        else if (list1.val < list2.val) {
            list1.next = mergeTwoLists(list1.next,list2);
            return list1;
        } else {
            list2.next = mergeTwoLists(list2.next,list1);
            return list2;
        }
    }
}
